Natural gas plants having trouble competing with solar?

[DanKegel]

This is probably the kind of thing SolarEagle has been worried about.

Reuters' reports that a fairly new and efficient natural gas-fired power plant has no takers for its output, and is shutting down:
http://www.reuters.com/article/us-ca...-idUSKCN0YV0BX
It mentions as one reason competition from solar and wind energy, and points to a report from Moody's that predicted the problem:
https://www.moodys.com/research/Mood...tor--PR_336126
The generator in question supposedly had high transmission costs, which made keeping it online harder.

I'm looking forward to seeing what LADWP's Maximum Renewable Energy Penetration Study has to say about economics of gas-fired power plants in an era of high renewable penetration. Supposedly it's done, but hasn't been published yet.

[nomadh]

Maybe someday we will just be using these plants during luls in green energy production

[SunEagle]

Maybe someday we will just be using these plants during luls in green energy production

Not if those plants have been shut down because they are no longer profitable to keep running. We need a tremendous amount of power generation which will not be provided only by natural gas plants when RE is not available.

In 2015 the US had a summer generating capacity of 1,063,722 MW. Of that 72% was from fossil fuel, 9.3% from nuclear, 16% from all RE (water, solar, wind, bio) and ~ 2% from pumped storage.

The estimate is more power will be consumed in the US in the coming years so more generation will be needed and available 24/7 or as you state "during the luls in green energy production". Hard to imagine the POCO's keeping their old plants sitting around waiting for the RE to stop so they could start them up and keep the lights on.

[Sunking]

Pure Dan BS and activism.

[DanKegel]

Wait, what? I'm pointing out a problem with going to high renewables penetration. This is something SunEagle is genuinely concerned about, and it's a real problem.

[DanKegel]

Not if those plants have been shut down because they are no longer profitable to keep running... Hard to imagine the POCO's keeping their old plants sitting around waiting for the RE to stop so they could start them up and keep the lights on.

Seems like it should be possible to have a fleet of gas-fired powerplants that fire up every evening at 5pm and run until 9am, and still make enough money to get a fair rate of return.

Nighttime electricity might have to be more expensive than daytime electricity to make that happen, but that's the way the duck curve is pointing us anyway.

[Sunking]

In 2015 the US had a summer generating capacity of 1,063,722 MW. Of that 72% was from fossil fuel, 9.3% from nuclear, 16% from all RE (water, solar, wind, bio) and ~ 2% from pumped storage..

If you look at what part of that 16% was solar, you would need a magnifying glass to see it on a chart.

[SunEagle]

Seems like it should be possible to have a fleet of gas-fired powerplants that fire up every evening at 5pm and run until 9am, and still make enough money to get a fair rate of return.

Nighttime electricity might have to be more expensive than daytime electricity to make that happen, but that's the way the duck curve is pointing us anyway.

Dan. It still comes down to how much does it cost the POCO to keep those gas fire plants working and ready to handle only the evening hours. That is a lot of capital just sitting around waiting to be ramped up to full power. There is also the amount of labor costs to man those plants for 24 hours for the days the sun does not come out. Most days no one would be working for 1 shift but how are you going to staff those crazy work hours.

For a gas plant to be profitable it needs to run close to peak as long as possible. That is the best way to be as efficient as possible and to get more kWh produced vs what it costs to do it.

[jflorey2]

Seems like it should be possible to have a fleet of gas-fired powerplants that fire up every evening at 5pm and run until 9am, and still make enough money to get a fair rate of return.

Here's the problem with that:
In general you can build two kinds of natural gas power plants. The first is a combined cycle baseload plant. These are quite efficient; the hot combustion gases first flow through a turbine, then flow through a boiler to drive a Carnot cycle plant. New designs are quoting up to 60% efficiency. This is good from many perspectives - cost (more kwhr per dollar of gas) CO2 emissions (less gas burned = less CO2) and pollution. However, they take a long time to start up; it can take such a plant hours to start up. A really fast combined cycle plant takes about 40 minutes. Such rapid starts are hard on the plant and reduce its life, though.

The other option are peakers. These are once-through gas turbines that start up quickly, within minutes (they are, after all, basically big jet engines) but have efficiencies closer to 20-30%.

So as a utility you have to decide which of the above to build. If you build out so much solar that you don't have much base load, it doesn't make sense to build much combined cycle. So you go with more peaker plants. But this means you burn more gas and pollute more, so you want to minimize your use of them. Does the addition of renewables counteract the increased CO2 generation? Sometimes yes, sometimes no. But it's not a slam-dunk to say "well, we will just generate power with renewables, then burn natural gas when we need to and it will work out cleaner."

[Engineer]

Great post! I've wondered why the producers don't just switch over to peakers as more solar comes online.

[DanKegel]

The other option are peakers. These are once-through gas turbines that start up quickly, within minutes (they are, after all, basically big jet engines) but have efficiencies closer to 20-30%.

The Carlsbad Energy Center repowering is going to use GE LMS-100 turbines which start up in 10 minutes, and are said to have an "LHV" efficiency of 46%. Anyone know what that translates to in overall efficiency to electricity?

[jflorey2]

The Carlsbad Energy Center repowering is going to use GE LMS-100 turbines which start up in 10 minutes, and are said to have an "LHV" efficiency of 46%. Anyone know what that translates to in overall efficiency to electricity?

Manufacturers like to use LHV (lower heating value) efficiency numbers because it ignores some of the energy present in the fuel; it has the effect of increasing apparent efficiency by about 10%. (This leads to the odd conclusion that some laboratory boiler designs are over 100% - because they ignore some of the energy obtained from the fuel.) Even so, the actual efficiency in that case would be around 35% which is excellent for straight-through turbines. Those sound like a compromise between fast startup (ten minutes instead of 3-5) and the efficiency of a combined cycle plant.

[Willaby]

Hard to imagine the POCO's keeping their old plants sitting around waiting for the RE to stop so they could start them up and keep the lights on.

I'd say they could come up with a new monthly fee to cover it. Not sure what it would be, an additional $10 would be a great value not to have batteries or a site generator, probably $20 would be good. Hopefully battery storage will come down in the future to compete.

[DanKegel]

Or they could charge more for nonrenewable electricity, to give people an incentive to shift their load towards when solar and wind are plentiful, and accurately reflect the higher running costs of the fossil plants.

[SunEagle]

To Willaby and Dan

Both of those are good examples that might help keep the gas plants both profitable and useful.

Biggest problem is getting people to change their lifestyle to use more power during the daytime when they are usually at work then at night when they are home. Unless they install some type of automated appliances (washer, dryer, etc.) I don't see how the majority of people that are not home will be able to shift their power usage.

[DanKegel]

Right,. appliances need to help.

Quite by accident, my dryer and dishwasher have delay settings, and now that I'm on TOU, I use 'em.

Hot water heaters, fridges, and hvac all could play along, but it needs to be automatic and easy to be accepted. Nobody really wants to fiddle with timers.

[SunEagle]

Right,. appliances need to help.

Quite by accident, my dryer and dishwasher have delay settings, and now that I'm on TOU, I use 'em.

Hot water heaters, fridges, and hvac all could play along, but it needs to be automatic and easy to be accepted. Nobody really wants to fiddle with timers.

It might be cheaper to just hire someone to stay in the home to run the major electrical loads during the daytime then at night.

[DanKegel]

You're joking, but nevertheless you imply that load shifting appliances would be expensive.

Since appliances already have microprocessors, the added hardware would be minor, maybe $10 for a ZigBee chip. The rest is "just software", heh heh.

[SunEagle]

The problem is that there is a large portion of the populace that both parents work and neither can be home to run the laundry or use their appliances when the sun is shining. They also do not have the funds to purchase the high end appliances that have the processor to run themselves. So charging higher rates at night for non RE generation power will really hurt the people that can't afford it anyway.

I know a portion of people can afford to pay for higher priced electric and the technology you are talking about but a larger portion of the populace live paycheck to paycheck. It would be a big hardship to charge them more because the power came from a gal plant instead of from RE.

[DanKegel]

Even low end appliances have microprocessors these days. I don't think it'd add more than $10 to the cost of an appliance to add a simple load shifting feature.

Every time efficiency regulations are proposed, industry moans that it's a huge burden and that it'll ruin everything; when the dust settles, it turns out that improving efficiency was easy. So it will be with this. And it'll benefit lower income people, who will be able to adjust to time of day pricing regardless of whether the cheap period is during the day or at night.